In Montgomery County, all court reporters in the Fifteenth Judicial Circuit appointed and holding office under the provisions of law applicable thereto, in addition to any other salary provided by the state, shall receive a total additional salary supplement in the amount of fifteen thousand six hundred dollars ($15,600) per annum from the county, which shall be payable in biweekly installments by the county out of the county general fund. The county salary supplement provided by this section shall be in lieu of any other county salary or compensation heretofore provided by law.